Apparent mismatch between extended x-ray absorption fine structure and diffraction structures of crystalline metastable WO3 phases.

ABSTRACT

The local structure of monoclinic, monohydrate, hexagonal, and pyrochlore WO3 phases was investigated by the extended x-ray absorption fine structure spectroscopy as preliminary studies of model compounds of amorphous and thin film WO3 based electrochromic species. In the four cases, we found a large W-O distribution of distances ranging from 1.70 to 2.35 A. The apparent discrepancy of these results and previously published crystal structures are discussed and interpreted as the detection of vacancies and local distortion disorder.